My youngest (year10) goes to one of the top public school (or private as most of MN call it) in the local town to us (as did his brothers).
He was a day boy but actually begged to weekly board as he thought it looked brilliant and his best mate was a full boarder. He goes Sunday night to Friday after school and absolutely loves it.
It's probably a bit different if he's 15 or so, as he's not necessarily that far from moving out and leaving you anyway, so he's just wanting to make the break a bit earlier.
But as for younger children, wouldn't it absolutely cut you to the quick for your child to be told that they don't want to live with you any more? I know they're often focusing on what they perceive to be the fun things about boarding school, but surely even most younger children must realise that choosing to live for most of your time at place B necessarily means that you're no longer living at place A?
Homes where marriages have broken down frequently experience many negative issues as a result of the children having to be moving from home to home all the time - even though it's from the home of one loving parent to the home of their other loving parent - I just don't see why happily married parents would choose to disrupt their child's home life and deliberately deprive them of one secure home.
I also think that much of the damage is swept under the carpet or not even realised until later by many of the children and their parents (who may be in denial anyway). I suppose, if you have gone down the BS route, you have no comparison of how things could have been if your family had remained living together.
I'm not personally a fan of sending very tiny children to nursery (for childcare rather than for pre-school experience), if you have a realistic option of one of their parents looking after them - all of those hours and special moments in their very early years that you miss; but I don't think you can compare children being away from you during the day to them actually having their main home moved away from their parents, whom they then don't see at all for weeks on end.
Although some people report having loved being at BS, the very high proportion of ex-boarders who report the devastating effect that they feel/have observed that it has had on their/their loved ones' lives tells me more than enough that it's not an avenue I'd ever want to pursue.
If I saw wild mushrooms growing in the woods as I walked on through, knowing that they might well be very safe and tasty but could equally be poisonous and dangerous.... I wouldn't mess around trying to work out which ones to chance: I'd just completely ignore the whole lot.